Conventionally, a spin coating method has been known as a method for coating a coating liquid on a substrate such as a semiconductor wafer or a glass substrate. The spin coating method refers to a method of spreading a coating liquid by dropping the coating liquid from a nozzle to a center of a substrate while rotating the substrate so that the coating liquid is diffused on the substrate by centrifugal force and spread to be coated on the substrate to form a coating film.
In such a spin coating method, the utilization efficiency is low because most of the dropped coating liquid is scattered out of the substrate. Thus, a slit coating method has recently been suggested as a coating method to replace the spin coating method.
The slit coating method refers to a method of coating using a nozzle having a slit-like discharge port. Specifically, in the slit coating method, a coating liquid, which is slightly exposed from the discharge port, is brought into contact with a substrate, and in this state, the nozzle and the substrate are relatively moved such that the coating liquid is spread on the substrate to form a coating film. According to this slit coating method, the utilization efficiency may be enhanced because it is possible to coat a coating liquid as needed on the substrate. See, e.g., Japanese Patent Laid-Open No. H8-173875.
Further, the nozzle disclosed in Japanese Patent Laid-Open No. H8-173875 is provided with a storage space configured to store the coating liquid. The nozzle discharges the coating liquid filled in the storage space from a discharge port through a slit-like path. A coating liquid supply system is connected to the storage space, and thus, the coating liquid is supplied from the coating liquid supply system such that the storage space is filled with the coating liquid.